Working machine, trouble diagnosis system of working machine, and maintenance system of working machine

ABSTRACT

A working machine failure diagnosis method for performing a failure diagnosis by transmitting and receiving signals through communication devices provided at a working machine and at an information management center, according to the present invention, includes: a first step in which a first signal related to a failure of the working machine is generated at the working machine and the first signal is transmitted to the information management center from the working machine via the communication devices; a second step in which, after the first signal is transmitted, the information management center generates a second signal for identifying a location of the failure based upon the first signal and the second signal is then transmitted from the information management center to the working machine via the communication devices; and a third step in which failure information corresponding to the first signal and the second signal is provided to an operator.

INCORPORATION BY REFERENCE

[0001] The disclosures of the following priority applications are hereinincorporated by reference:

[0002] Japanese Patent Application No. 2001-137809 filed May 8, 2001

[0003] Japanese Patent Application No. 2001-219601 filed Jul. 19, 2001

TECHNICAL FIELD

[0004] The present invention relates to a failure diagnosis andmaintenance performed on a working machine and, more specifically, itrelates to a failure diagnosis and maintenance performed on aconstruction working machine such as a hydraulic excavator.

BACKGROUND ART

[0005] There are systems in the related art in which information(operation data) from construction working machines is transmitted to aninformation management center where operation data are used to forecastwhether or not there is a failure (e.g., Japanese Laid-Open PatentPublication No. 2000-259729). The forecast information generated at thecenter is provided to the maintenance personnel and a maintenance personperforms maintenance work or the like based upon the information thusprovided.

[0006] However, in the system disclosed in the publication quoted above,the information from the center is not directly provided to the operatoroperating the working machine and, as a result, it takes a considerablelength of time for the operator to ascertain the exact location of thefailure and the cause of the failure in the working machine. This givesrise to a concern that when a failure occurs, the operator may not beable to take appropriate action in a timely manner.

[0007] In addition, failure repair data or maintenance completion datatransmitted by the service personnel upon completing a repair on afailed machine or completing maintenance work are provided to a databaseat the center server through a manual input by the service personnel ora clerk in the office to which the service personnel report. Undercertain circumstances, the data can be inadvertently left unentered orinput erroneously. This, in turn, leads to a problem in that anunpredicted failure can occur through a failure to perform appropriatemaintenance on the individual working machines.

DISCLOSURE OF THE INVENTION

[0008] The present invention provides a working machine, a failurediagnosis system for working machines and a maintenance system forworking machines that provide an operator with appropriate informationindicating a failure location in a working machine and the like andenable maintenance work to be performed on the working machine.

[0009] A working machine failure diagnosis method for performing afailure diagnosis by transmitting and receiving signals throughcommunication devices provided at a working machine and at aninformation management center, according to the present invention,comprises: a first step in which a first signal related to a failure ofthe working machine is generated at the working machine and the firstsignal is transmitted to the information management center from theworking machine via the communication devices; a second step in which,after the first signal is transmitted, the information management centergenerates a second signal for identifying a location of the failurebased upon the first signal and the second signal is then transmittedfrom the information management center to the working machine via thecommunication devices; and a third step in which failure informationcorresponding to the first signal and the second signal is provided toan operator.

[0010] In this working machine failure diagnosis method, it is preferredthat the first step starts upon a detection of an abnormal state at theworking machine.

[0011] Also, it is preferred that the first step starts as anabnormality occurrence signal is input at the working machine when anabnormality has occurred at the working machine.

[0012] Also, it is preferred that there are further provided a fourthstep in which a signal related to a service request for the identifiedfailure location is transmitted from the working machine to theinformation management center, and a fifth step in which a servicingcost and a length of servicing time are calculated at the informationmanagement center based upon the signal related to the service requestand information indicating the cost and the length of time istransmitted to the working machine.

[0013] Also, it is preferred that there are further provided a fourthstep in which a signal related to a service request for the identifiedfailure location is transmitted from the working machine to theinformation management center, and a fifth step in which a time point atwhich a service person is expected to arrive at a site is calculated atthe information management center based upon the signal related to theservice request and information indicating the time point is transmittedto the working machine.

[0014] A working machine failure diagnosis system according to thepresent invention comprises: a first signal generating device thatgenerates at a working machine a first signal related to a failure ofthe working machine; a first transmission device that transmits thefirst signal from the working machine to an information managementcenter; a second signal generating device that generates at theinformation management center a second signal for identifying a locationof the failure based upon the first signal after the first signal istransmitted thereto; a second transmission device that transmits thesecond signal from the information management center to the workingmachine; and an informing device that provides an operator with failureinformation corresponding to the first signal and the second signal.

[0015] In this working machine failure diagnosis system, it is preferredthat: the working machine includes a detection device that detects anabnormal state therein; and when an abnormal state is detected by thedetection device, the first signal generating device generates the firstsignal based upon detection results.

[0016] Also, it is preferred that: the working machine includes anoperating unit that is operated when an abnormality occurs therein; andwhen an abnormality occurrence signal is input through the operatingunit, the first signal generating device generates the first signalbased upon the abnormality concurrence signal.

[0017] Also, it is preferred that: the second signal containsinformation for identifying the failure location; and the informingdevice informs the operator of the identified failure location. In thiscase, it is preferred that: the information management center includes aservice management device that calculates a servicing cost and a lengthof servicing time after a signal related to a service request istransmitted from the working machine following identification of thefailure location; and the second signal generating device generates thesecond signal that contains information indicating the servicing costand length of servicing time. Also, it is preferred that: theinformation management center includes a schedule management device thatcalculates a time point at which a service person is expected to arriveat a site after a signal related to a service request is transmittedfrom the working machine following identification of the failurelocation; and the second signal generating device generates the secondsignal that contains information indicating the arrival time point.

[0018] A working machine according to the present invention comprises: asignal generating device that generates a signal related to failureinformation; a transmission device that transmits the signal which hasbeen generated to an information management center; a reception devicethat receives a signal related to a failure diagnosis returned from theinformation management center in response to the signal transmitted viathe transmission device; and an informing device that provides failureinformation based upon the signal that has been received.

[0019] In this working machine, it is preferred that: there is furtherprovided an automatic abnormality detection device that automaticallydetects an abnormal state in the working machine; and the signalgenerating process generates the signal related to the failureinformation when the abnormal state is detected by the automaticabnormality detection device.

[0020] Also, it is preferred that: there are further provided an inputdevice through which a failure diagnosis instruction is received from anoperator, and an abnormality detection device that detects whether ornot an abnormal state is present in the working machine when the failurediagnosis instruction is received through the input device; and thesignal generating process generates the signal related to the failureinformation when the abnormal state is detected by the abnormalitydetection device.

[0021] Also, it is preferred that: the signal generating device alsogenerates a signal related to a service request for an identifiedfailure location; the transmission device transmits the signal relatedto the service request to the information management center; thereception device receives a signal related to a servicing cost and alength of servicing time generated at the information management centerbased upon the signal related to the service request; and the informingdevice provides information related to the servicing cost and the lengthof servicing time based upon the signal related to the cost and thelength of time which has been received.

[0022] Also, it is preferred that: the signal generating device furthergenerates a signal related to a service request for an identifiedfailure location; the transmission device transmits the signal relatedto the service request to the information management center; thereception device receives a signal related to a time point at which aservice person is expected to arrive at a site generated at theinformation management center based upon the signal related to theservice request; and the informing device provides information relatedto the time point at which the service person is expected to arrive atthe site based upon the signal related to the arrival time point whichhas been received.

[0023] A computer program product according to the present inventionthat can be read by a computer installed in a working machine, containsa working machine failure diagnosis program, and the working machinefailure diagnosis program comprises: a signal generation instructioncode for generating a signal related to failure information; atransmission instruction code for transmitting the generated signal toan information management center; a reception instruction code forreceiving a signal related to a failure diagnosis returned from theinformation management center in response to the signal transmitted inconformance to the transmission instruction code; and an informinginstruction code for providing failure information based upon thereceived signal.

[0024] An information management center according to the presentinvention that exchanges signals with a working machine comprises: areception device that receives a signal related to failure informationtransmitted from the working machine; a signal generating device thatgenerates a response signal related to a failure diagnosis in responseto the signal; and a transmission device that transmits the responsesignal to the working machine.

[0025] A computer program product according to the present inventionthat can be read by a computer installed at an information managementcenter engaged in signal exchange with a working machine, contains aworking machine failure diagnosis program, and the working machinefailure diagnosis program comprises: a reception instruction code forreceiving a signal related to failure information transmitted from theworking machine; a signal generating instruction code for generating aresponse signal related to a failure diagnosis in response to thesignal; and a transmission instruction code for transmitting theresponse signal to the working machine.

[0026] A working machine maintenance system according to the presentinvention comprises: a plurality of working machines; and a centerserver that manages maintenance on the plurality of working machines byengaging in data exchange through bidirectional communication with eachof the plurality of working machines via a communication line, and: theworking machines each include an operation data storage device thatstores operation data and maintenance data, an operation device operatedto enter a maintenance work completion, a data transmission device thattransmits the operation data, maintenance work completion data providedthrough the operation device and the maintenance data to the centerserver, a data reception device that receives data related tomaintenance information transmitted from the center server and a displaydevice at which the maintenance information is displayed; and the centerserver includes a data reception device that receives the operationdata, the maintenance work completion data and the maintenance data thathave been transmitted, an operation database in which the operation dataare stored, a maintenance database in which the maintenance data arestored, a calculation device that calculates maintenance timing basedupon the operation data stored in the operation database and themaintenance data stored in the maintenance database and a datatransmission device that transmits data related to the maintenanceinformation including the maintenance timing to a working machine.

[0027] In this working machine maintenance system, it is preferred that:maintenance work, a completion of which is signaled through an inputoperation at the operation device, includes failure repair work; and themaintenance data include failure location data indicating a failurelocation at the working machine.

[0028] A working machine according to the present invention comprises: acommunication device that exchanges information via a communication linethrough bidirectional communication with a center server managingmaintenance on a plurality of working machines; an operation device atwhich an input operation signaling a maintenance work completion isreceived; a storage device in which maintenance completion informationrelated to the maintenance work completion is stored; and a controldevice that transmits the maintenance completion information stored inthe storage device to the center server via the communication devicewhen the input operation signaling the maintenance work completion isreceived at the operation device.

[0029] In this working machine, it is preferred that: there is furtherprovided a display device; the control device receives maintenanceinstruction information related to a maintenance instruction transmittedfrom the center server via the communication line and displays themaintenance instruction information that has been received at thedisplay device. In this case, it is preferred that operation informationrelated to an operation of the working machine is stored in the storagedevice; and the control device transmits the operation informationstored in the storage device to the center server via the communicationdevice with predetermined timing.

[0030] A computer program product according to the present inventionthat can be read by a computer installed at a working machine, containsa working machine maintenance program, and the working machinemaintenance program comprises: an operation instruction code forreceiving an input operation signaling a maintenance work completion atthe working machine via an input device; a storage instruction code forstoring maintenance completion information related to the maintenancework completion at the working machine into a storage device; and atransmission instruction code for transmitting the maintenancecompletion information stored in the storage device via a communicationdevice to a center server managing maintenance on a plurality of workingmachines upon receiving the input operation signaling the maintenancework completion.

[0031] A center server according to the present invention that managesmaintenance on a working machine, comprises: a communication device thatexchanges information with a working machine via a communication linethrough bidirectional communication; a maintenance database in whichinformation related to the maintenance on the working machine is stored;and a control device that receives maintenance completion informationrelated to a maintenance work completion at the working machinetransmitted from the working machine via the communication device andstores the received maintenance completion information into themaintenance database.

[0032] In this center server, it is preferred that: there is furtherprovided an operation database in which operation information related toan operation of the working machine is stored; and the control devicereceives the operation information transmitted from the working machinevia the communication line and stores the received operation informationinto the operation database. In this case, it is preferred that thecontrol device generates maintenance instruction information related toa maintenance instruction for the working machine based upon theinformation related to the maintenance on the working machine stored inthe maintenance database and the operation information related to theoperation of the working machine stored in the operation database andtransmits the maintenance instruction information that has beengenerated to the working machine via the communication device.

[0033] A computer program product according to the present inventionthat can be read by a center server managing maintenance on a workingmachine, contains a working machine maintenance management program, andthe working machine maintenance management program comprises: areception instruction code for receiving maintenance completioninformation related to a maintenance work completion at the workingmachine transmitted from the working machine via a communication device;and a storage instruction code for storing the maintenance completioninformation that has been received into a maintenance database.

[0034] It is preferred that each of the above computer program productsis a recording medium having the working machine failure diagnosisprogram recorded therein. Or it is preferred that each of the abovecomputer program products is a carrier wave on which the working machinefailure diagnosis program is embodied as a data signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a schematic block diagram of the failure diagnosissystem achieved in a first embodiment;

[0036]FIG. 2 is a side elevation of a hydraulic excavator in which thefailure diagnosis system in the first embodiment may be adopted;

[0037]FIG. 3 presents a flowchart of an example of the informationtransmission/reception processing that may be executed in the controllerof the hydraulic excavator in the first embodiment;

[0038]FIG. 4 presents a flowchart of an example of the informationtransmission/reception processing executed in the center server in thefirst embodiment;

[0039]FIG. 5 is a diagram of the characteristics of a boom angle sensor;

[0040]FIG. 6 presents a flowchart of a specific procedure followed inthe signal transmission/reception in the failure diagnosis system in thefirst embodiment;

[0041]FIG. 7 presents a flowchart of a specific procedure followed inthe signal transmission/reception in the failure diagnosis systemachieved in a second embodiment;

[0042]FIG. 8 presents a flowchart of an example of a variation of theprocedure shown in FIG. 7;

[0043]FIG. 9 a system block diagram showing the overall structure of themaintenance system for working machines achieved in a third embodiment;

[0044]FIG. 10 is a block diagram of the maintenance monitor devicemounted at the hydraulic excavator;

[0045]FIG. 11 is a block diagram showing the structure adopted in, andthe processing executed in the essential part of the management server;and

[0046]FIG. 12 presents a flowchart of the bi-directional datatransmission between the maintenance monitor device at the hydraulicexcavator and the management server.

BEST MODE FOR CARRYING OUT OF THE INVENTION

[0047] First Embodiment

[0048] In reference to FIGS. 1˜6, the first embodiment of the failurediagnosis system according to the present invention is explained.

[0049]FIG. 1 is a schematic block diagram of the failure diagnosissystem achieved in the first embodiment and FIG. 2 is a side elevationof a hydraulic excavator in which the failure diagnosis system may beadopted. As shown in FIG. 2, a hydraulic excavator 1 includes atraveling lower-structure 61, a swinging upper-structure 62 rotatablymounted on the traveling lower-structure 61 and a work device 63comprising a boom 63A, an arm 63B and a bucket 63C supported from theswinging upper-structure 62. A control device 10 and a display device 11such as a monitor are installed in an operator's cab 64. The controldevice 10 includes a controller 12 and a communication device 13 towhich an antenna 14 is connected. A plurality of such hydraulicexcavators 1 are deployed on the ground and they exchange informationwith a center 3 via a communication satellite 2 as shown in FIG. 1.

[0050] Numerous sensors 15 are provided at the hydraulic excavator 1 todetect the engine rotation rate, the hydraulic pump pressure level, thepilot pressure level set in response to an operation of an operatinglever, the level of the load applied to an actuator which may be, forinstance, a hydraulic cylinder and the like. A command for a signaltransmission to the center 3, a command for image display at the displaydevice 11 and the like are input through the operator's key operationsor the like at an input unit 16. A warning generator 17 generates awarning based upon a signal provided by a sensor 15 to alert theoperator that an abnormality has manifested in the hydraulic excavator.

[0051] Signals from the sensors 15, the input unit 16 and thecommunication device 13 are input to the controller 12 and are stored ina memory 18. The controller 12 includes a display control unit 19 and atransmission control unit 20. The display control unit 19 controls theimage display at the display device 11, as shown in, for instance, FIG.6 which is to be detailed later by using the signals from the input unit16 and the communication device 13. The controller 12 createstransmission data based upon the signals stored in the memory 18 andtransmits the transmission data thus prepared to the center 3 withpredetermined timing through the processing (see FIG. 3) which is to beexplained later.

[0052] The transmission data created at the controller 12 includes IDdata used to identify the model type and the unit number of thehydraulic excavator 1, data indicating the date of operation and theoperating hours of the hydraulic excavator 1, details of warninggeneration, the frequency distributions of the output values from theindividual sensors relative to the engine rotation rate, details ofparts replacement and details of failures. An abnormality signalprovided by a sensor 15 enables a detection as to whether or not afailure has occurred. The failure details indicate various abnormalitiessuch as an abnormal voltage output from a sensor 15, an abnormal enginerotation rate, an abnormal hydraulics pressure level, an abnormalbattery charge and an abnormal cooling water temperature, which areprovided as coded data. For instance, a failure code “1” is transmittedin the event of a failure at the boom angle sensor, a failure code “2”is transmitted in the event of a failure at an arm angle sensor and afailure code “3” is transmitted in the event of a failure at anelectromagnetic valve.

[0053] These transmission data are received at a communication device 31of the center 3 via the communication satellite 2 and are thentransferred to a management server 32 at the maker to be stored into adatabase 33. The management server 32 recognizes any failure in thehydraulic excavator 1 through the processing (see FIG. 4) to be detailedlater and transmits specific information to the hydraulic excavator 1.At the database 33, the transmission data from the hydraulic excavator 1are cumulatively stored in correspondence to the individual machinenumbers and model types. This makes it possible to keep track of thetotal length of operating time and the lengths of time over which thevarious parts have been used for each excavator. In addition, a failurediagnosis procedure for identifying a failure location and the cause ofthe failure in correspondence to a given failure code is stored inmemory at the database 33.

[0054] A user's terminal 34 is connected to the center via, forinstance, a telephone line. Thus, the user is able to exchange necessaryinformation with the center 3. It is to be noted that the user may be aservice department or a dealer of the hydraulic excavator maker and thefailure information can be transmitted to the nearest service engineeras well.

[0055] Now, a specific example of the information transmission/receptionprocessing is explained in reference to the flowcharts presented inFIGS. 3 and 4. It is to be noted that FIG. 3 shows the processingexecuted at the transmission control unit 20, whereas FIG. 4 shows theprocessing executed at the server 32. These processing programs arestored in a storage device (not shown) within the transmission controlunit 20 and a storage device (not shown) at the server 32.

[0056] As shown in FIG. 3, the signals input from the sensors 15, theinput unit 16 and the communication device 13 are read in step S1 andthese input signals are stored into the memory 18 in step S2. Next, adecision is made as to whether or not a transmission command has beenissued in step S3. A transmission command is output over predeterminedtime intervals following the work start or in response to an operationof the input unit 16 by the operator. It is to be noted that atransmission command may be output at the completion of the work or at apredetermined time point during the day (e.g., late at night). If anaffirmative decision is made in step S3, the operation proceeds to stepS4 to prepare the transmission data based upon the data stored in thememory 18, and the data thus prepared are transmitted instep S5 beforethe operation returns to step S1.

[0057] The data transmitted from the communication device 13 arereceived at the communication device 31 at the center 3. As shown inFIG. 4, the received data are read at the server 32 in step S11, and thedata are then saved into the database 33 in step S12. Next, in step S13,a decision is made as to whether or not a failure has occurred bychecking for failure codes and if an affirmative decision is made, theoperation proceeds to step S14, whereas if a negative decision is made,the operation returns to step S11. In step S14, the database 33 isaccessed and transmission data corresponding to the failure code and thereceived data are prepared. An example of these transmission data is tobe explained later in reference to FIG. 6. Then, the transmission dataare transmitted in step S15 before the operation returns to step S11.

[0058] Next, the operation of the failure decision-making device thatcharacterizes the first embodiment is explained in further detail. It isto be noted that the following explanation is given on the assumptionthat the boom angle sensor has output an abnormality signal.

[0059]FIG. 5 is a diagram of the characteristics of the boom anglesensor 15. When the sensor 15 is engaged in normal operation, the outputvoltage fluctuates within the range of 0.5V 4.5V in correspondence tothe boom angle. If the output voltage level becomes equal to or lowerthan 0.25V or equal to or higher than 4.75V (the shaded areas) thecontroller 12 judges that an abnormality has occurred in the sensoroutput value due to disconnection or shorting. In this case, the failurelocation (the cause of the failure) may be the sensor 15 itself, theharness, the power source, the controller 12 or the like. Accordingly, afailure diagnosis is executed to as explained below to identify theexact failure location.

[0060]FIG. 6 shows a specific procedure which is taken in the signaltransmission/reception between the hydraulic excavator 1 and the center3. As the boom angle sensor 15 outputs an abnormality signal (step S21),the warning generator 17 generates a warning and, at the same time, thedisplay control unit 19 generates a control signal to bring up a displayof a question as to whether or not a failure diagnosis is to be executedat the display device 11, as shown in the figure (step S22). If theoperator selects “yes” through an operation of the input unit 16 inresponse to this question, the transmission data (failure data) aretransmitted to the center 3 together with the failure code “1” throughthe processing explained earlier (step S3->step S4->step S5). It is tobe noted that depending upon the seriousness and the details of thefailure, the failure data may be forcibly transmitted to the center 3regardless of whether the operator selects “yes” or “no”.

[0061] At the server 32, the database 33 is accessed through theprocessing described earlier (step S13->step S14->step S15), the failurediagnosis procedure corresponding to the failure code “1” is read and afirst command is transmitted to the hydraulic excavator 1 (step S23). Inresponse to this signal, an electrical conduction check command isbrought up on display at the display device 11, as shown in the figure(step S24). The operator checks the state of electrical conduction atthe harness connector by following the instruction on display to verifywhether or not the state of electrical conduction is normal. If“abnormal” is selected through an operation of the input unit 16, theserver 32 accesses the database 33, identifies the cause of the failureby using the transmitted information and sends information indicatingthe identified cause to the excavator 1 (step S25). As a result,information such as that shown in the figure is brought up on display atthe display device 11 (step S26) so that the operator is able toidentify the cause of the failure detected in the sensor 15 as a harnessmalfunction.

[0062] If, on the other hand, “normal” is selected through an operationof the input unit 16 in step S24, the server 32 transmits a secondcommand to the excavator 1 (step S27). In response to this signal, adisplay of a resistance value measurement command is brought up at thedisplay device 11 as shown in the figure (step S28). The operatorfollows this instruction and measures the resistance value at theconnector of the sensor 15 to verify whether or not the resistance valueis in the normal range. Then, if “abnormal” is selected, the server 32accesses the database 33 to identify the cause of the failure and sendsinformation indicating the identified cause to the excavator 1 (stepS29). As a result, information such as that shown in the figure isbrought up on display at the display device 11 (step S30) so that theoperator can identify the failure as a malfunction in the sensor 15itself.

[0063] If “normal” is selected in step S28, the server 32 accesses thedatabase 33, identifies the cause of the failure based upon theaccumulated information and sends information indicating the identifiedcaused to the excavator 1 (step S31) In this case, the cause of thefailure is judged to be a malfunction of the controller 12 andinformation indicating the cause is brought up at the display device 11as shown in the figure (step S32). Through the processing describedabove, the location of the failure can be identified in the event of anabnormality detected in the boom angle sensor.

[0064] It is to be noted that while an explanation is given above on anexample in which a failure diagnosis is executed for the boom anglesensor 15, a failure diagnosis can be executed in a similar manner foran electromagnetic proportional valve as well. In the latter case, ifthe value which is actually detected is equal to or higher than 3 MPawhen the command value for the electromagnetic proportional valve drivenby an electric lever is, for instance, equal to or lower than 1 MPa, itmay be judged that a failure has occurred in the electromagneticproportional valve and the failure code “3” may be transmittedaccordingly. Then, in response to a command issued by the server 32, theoperator should take an appropriate action such as checking the state ofelectrical conduction at the harness.

[0065] As described above, when the first embodiment, in which signalsare exchanged between the hydraulic excavator 1 and the server 32 viathe communication satellite 2 and information with regard to a failureat the excavator 1 is displayed at the display device 11 in a dialogformat is adopted, the operator is able to ascertain the location of thefailure with ease. As a result, the operator is able to take appropriatepost-failure action. In addition, since a failure diagnosis is startedin response to the output of an abnormality signal from a sensor 15, thefailure diagnosis is performed in a timely manner. Furthermore, sincethe server 32 accesses the database 33 to identify the location of thefailure, it is not necessary to store in memory a large volume of dataat the excavator and thus, it is possible to utilize the availablestorage capacity at the excavator in an efficient manner. Moreover, thefailure data are coded and thus, the data structure is simpler.

[0066] Second Embodiment

[0067] The second embodiment of the present invention is now explainedin reference to FIGS. 7 and 8. While the image displayed at the displaydevice 11 is automatically switched in the event of a failure at asensor 15 and the operation enters the failure diagnosis mode in thefirst embodiment, the operation enters the failure diagnosis mode inresponse to a menu selection operation performed by the operator in thesecond embodiment. The following explanation focuses on the differencefrom the first embodiment.

[0068] The second embodiment differs from the first embodiment in thespecific procedure followed in the signal to transmission/receptionbetween the hydraulic excavator 1 and the center 3. If any problemoccurs while driving the hydraulic excavator 1, the operator selects thefailure diagnosis mode by operating the input unit 16. In response, aninitial screen such as that shown in FIG. 7, for instance, is thebrought up at the display device 11 (step S41). In this example, “notable to move the front” is selected from the display screen. At thedatabase 33, the procedures corresponding to various selection signalsare stored in advance, and the server 32 reads the procedurecorresponding to the specific selection signal from the database 33 andtransmits a first command to the excavator 1 (step S42). In response, aquestion such as that shown in the figure is brought up on display atthe display device 11 (step S43).

[0069] If “boom-up” is selected as the answer to this question, theserver 32 transmits a second command corresponding to the selectionsignal (step S44) and the command is displayed as shown in the figure atthe display device 11 (step S45). As the operator performs a boom-upoperation in response to this command, the values of the detected pumppressure and pilot pressure during the boom-up operation are transmittedto the server 32. The server 32 makes a decision as to whether or notthe transmitted detection values are in normal ranges (step S46) andtransmits a third command if detected values are in abnormal ranges,i.e., if they are much lower than the preset values. In response, thecommand is displayed as shown in the figure at the display device 11(step S48). If the operator selects “normal” upon checking the harnessin response to this command, the server 32 identifies the location ofthe failure based upon the accumulated information (step S49). As aresult, the location of the failure and a service contact are brought upon display together as shown in the figure at the display device 11(step S50).

[0070] If, on the other hand, it is decided in step S46 that the valuesof the detected pump pressure and pilot pressure are in the normalranges, the server 32 transmits a fourth command (step S51) and thecommand is displayed at the display device 11 as shown in the figure(step S52). If the operator selects “normal” upon checking for any oilleak in response to this command, the server 32 identifies the locationof the failure based upon the accumulated information (step S53) As aresult, the location of the failure and a service contact are brought upon display together as shown in the figure at the display device 11(step S54).

[0071] While the location of the failure and the service contact aredisplayed in step S50 and step S54 as described above, a service personmay be contacted through a question and answer format as shown in FIG.8, instead. For instance, after the location of the failure isidentified as the electromagnetic valve, information such as that shownin FIG. 8 is brought upon display at the display device 11 (step S55).If “contact online” is selected at this point, the server 32 accessesthe database 33 and calculates the price of the replacementelectromagnetic valve, the length of the standard labor time and thecorresponding repair fee (step S56A).

[0072] In this system, each service engineer enters his work schedulefor the day in advance by using his own personal computer or the like,and the schedule information is transmitted to the center 3 where it isstored into the database 33. In addition, the hydraulic excavator 1 ismounted with a position measuring instrument such as a GPS unit andthus, information indicating the current position of the hydraulicexcavator 1 is transmitted to the center 3 in real time. Based upon theinformation, the server 32 determines the closest service department tothe work site and the service engineer who can most quickly bedispatched to the site and transmits information with regard to theservice request to the service engineer via the service department or bybypassing the service department. The service engineer, in turn, sends aresponse to the information indicating whether or not he is able toprovide his service and the estimated time of arrival at the work siteto the server 32 (step S56B).

[0073] The information obtained in steps S56A and S56B is transmitted tothe excavator 1 where the information is brought up on display at thedisplay device 11 as shown in the figure (step S57). Accordingly, theoperator verifies the length of the labor time, the fee and the like andmakes a decision as to whether or not a repair order is to be placed. If“yes” (the repair is ordered) is selected in step S57, this command isrelayed to the service engineer via the center and the service engineeris dispatched to the site (step S58).

[0074] As explained above, in the second embodiment in which the failurediagnosis mode is selected through a menu operation by the operator, thelocation where a problem has occurred can be identified any time at theoperator's request. In the event of a failure, a service request can beissued through a selection operation by the operator carried out in adialogue format and thus, he does not need to go through thetraditional, time-consuming process of repair order placement. Inaddition, since information such as the parts price, the length of timerequired for the repair work and the estimated time of arrival of theservice engineer becomes instantly available, the efficiency and theoperability are improved.

[0075] It is to be noted that while the information regarding a failurein the hydraulic excavator 1 is displayed at the display device 11 toalert the operator in the embodiment, the operator may be provided withthe information through an audio message instead. In addition, whilesignals are exchanged over a plurality of times between the hydraulicexcavator 1 and the center 3 in the processing shown in FIGS. 6˜8,signals may be transmitted once each from the hydraulic excavator 1 andthe center 3 instead. While the present invention is adopted inconjunction with hydraulic excavators in the embodiment described above,it may instead be adopted in other construction machines.

[0076] Third Embodiment

[0077]FIG. 9 shows the overall structure of the maintenance system forworking machines achieved in the third embodiment. Three hydraulicexcavators 111A, 111B and 111C are shown in the figure as an example ofworking machines subscribing to the maintenance service. However, themaintenance work may be performed on working machines other thanhydraulic excavators. While numerous hydraulic excavators are managedthrough this maintenance system for upkeep, management and maintenancein reality, only three hydraulic excavators 111A˜111C, i.e., excavator1, excavator 2 and excavator 3 are shown in the figure to simplify theexplanation. These hydraulic excavators are assigned to individual worksites. The hydraulic excavators 111A˜111C, which are managed through themaintenance system achieved in the embodiment as detailed later includemaintenance monitor devices adopting structures identical to oneanother. The hydraulic excavators 111A˜111C are each mounted with acontrol device constituted of a computer, and the control deviceincludes a communication device, an operation control unit, anarithmetic processing unit, a storage unit and the like. These controldevices enable the hydraulic excavators 111A˜111C to exchangeinformation with an external partner via an electrical communicationline. The maintenance monitor devices mentioned earlier are eachrealized in the form of a control device adopting the structuredescribed above.

[0078] A management server (or a center server) 112 is provided tomanage the maintenance of the plurality of the hydraulic excavators111A˜111C. The management server 112 is installed at a base station,whereas the hydraulic excavators 111A˜111C are assigned to work sites atremote locations. The management server 112 is operated by the maker, arental company, a sales company, a maintenance management company or thelike. The management server 112 comprises a computer 113, various typesof input devices 114, a display device (display) 115, an operationdatabase 116, in which operation data are stored, and a maintenancedatabase 117, in which maintenance data (data on regular inspections,failure repair data, data on replacement of parts and consumables) arestored. The computer 113 at the management server 112 includesfunctional units such as the communication device and the arithmeticprocessing unit and exchanges information (commands, data and the like)with each of the hydraulic excavators 111A˜111C at remote locations viathe electrical communication line.

[0079] The electrical communication line (a data communication path)connects the hydraulic excavators 111A˜111C with the management server112. The electrical communication line is constituted of a communicationsatellite 118, a ground station 119 and a public line or the Internet120. The hydraulic excavators 111A˜111C and the management server 112engage in bidirectional communication through their communicationdevices and also via the electrical communication line adopting thestructure described above.

[0080] Arrows 121, 122, 123 and 124 in FIG. 9 indicate various states inwhich communication is in progress. However, these arrows simplyrepresent an example.

[0081] The arrow 121 indicates a state in which operation data 125 aretransmitted from the hydraulic excavator 111A to the management server112 via the communication satellite 118, the ground station 119 and thelike. The operation data 125, shown as a block of data, indicate thefrequency distributions of the engine rotation rate, the hydraulicoperating fluid temperature, the radiator water temperature, the pumppressure and the like at the hydraulic excavator 111A. The operationdata 125, which are obtained at the control device through variousoperation sensors to ascertain the operating state of the hydraulicexcavator 111A while it is engaged in work, are stored in the storageunit. The operation data are collected and saved at the maintenancemonitor device mentioned earlier. The operation data are transmitted bythe control device and the communication device at the hydraulicexcavator 111A on a regular basis or as necessary to the managementserver 112 where they are recorded into the operation database 116.

[0082] The arrow 122 indicates a state in which a command related tomaintenance is transmitted from the management server 112 to thehydraulic excavator 111B. The contents of this maintenance command aredisplayed as a message, e.g., “change oil”, at an on-vehicle displaydevice 126 provided inside the operators cab of the hydraulic excavator111B. In FIG. 9, the on-vehicle display device 126 is shown in anenlargement for emphasis.

[0083] The arrow 123 indicates a state 129 in which a maintenancecompletion signal is transmitted to the management server 112 inresponse to an ON operation of a maintenance complete switch 127 at thehydraulic excavator 111C by a service engineer or operator 128. Theservice engineer performs maintenance work related to the itemsdisplayed at the on-vehicle display device 126, for instance, andpresses the maintenance complete switch 127 when the work is completed.As a result, the length of operating time having elapsed up to the workcompletion and the maintenance work items are automatically transmittedto the management server 112 and the transmitted contents are recordedinto the maintenance database 117 at the management server 112.

[0084] As described above, necessary data and commands are exchangedthrough the bidirectional communication between the individual hydraulicexcavators 111A˜111C assigned at the various work sites and themanagement server 112.

[0085] In addition, a user 131 can access the management server 112 viathe Internet 130 by using an Internet terminal device 132. The user 131is a party involved in the operation of one of the hydraulic excavators111A˜111C. The user 131 accesses the homepage of the management server112 that provides maintenance information, receives permission forinformation access by entering his ID and password and obtains themaintenance information on the relevant hydraulic excavator or the like.

[0086] Now, in reference to FIG. 10, a specific structure that may beadopted in the maintenance monitor devices provided in the hydraulicexcavators 111A˜111C is explained.

[0087] A maintenance monitor device 141 is realized in the form of acontrol device 142 constituted of a computer. The control device 142comprises a CPU 143, a storage unit (memory) 144, a sensor inputinterface (I/F) 145, a display interface (I/F) 146 and a communicationinterface (I/F) 147. Signals indicating the operating state of thehydraulic excavator detected by operation sensors 148 provided at thevarious mechanical components including the engine and the hydraulicfuel supply system are input to the CPU 143 via the sensor inputinterface 145. The CPU 143 stores operation data based upon the variousoperation signals input thereto into the storage unit 144. At thestorage unit 144, a program and data which enable the execution of thevarious types of processing are stored. The data stored at the storageunit 144 include the data indicating the machine number and the modeltype, maintenance data and maintenance information in addition to theoperation data described above. The maintenance complete switch 127explained earlier is provided at the operator's cab of the hydraulicexcavator. An ON operation signal generated at the maintenance completeswitch 127 is input to the CPU 143. The control device 142 includes adisplay device 149. This display device 149 corresponds to theon-vehicle display device shown in FIG. 9. Display data are transmittedfrom the CPU 143 via the display interface 146 and maintenance relatedinformation is displayed at the screen of the display device 149. Themaintenance monitor device 141 includes a communication device 150. Thecommunication device 150 constitutes a data communication terminal.Various types of data are exchanged between the control device 142 andthe management server 112 via the communication device 150. Thecommunication device 150 is connected to the CPU 143 via thecommunication interface 147.

[0088] Details of the processing executed by the maintenance monitordevice 141 adopting the structure described above are provided below inrelation to the communication with the management server 112.

[0089] Next, in reference to FIG. 11, the structure of the managementserver 112 and the essential processing executed in the managementserver 112 are explained in detail. The management server 112 in FIG. 11includes data storage units, i.e. the operation database (operation DB)116 and the maintenance database (maintenance DB) 117, as describedearlier. The various types of data transmitted from the hydraulicexcavators 111A˜111C to the management server 112 via the electricalcommunication line are received at a communication reception unit 151 ofthe management server 112. The operation data are then passed throughthe communication reception unit 151 and stored (recorded) in theoperation database 116. In the operation database 116, each set ofoperation data is recorded as a file 116 a corresponding to a specificmachine number and model type. In addition, each set of maintenance datais recorded at the maintenance database 117 as a file 117 acorresponding to a specific machine number and model type. The computer113 of the management server 112 includes a maintenance timingcalculation unit 152 as a functional means. The maintenance timingcalculation unit 152 calculates the correct timing with whichmaintenance (repairs, parts replacement) should be performed on variousparts (maintenance requiring parts) of the working machines incorrespondence to the individual machine numbers a model types basedupon maintenance criteria obtained through statistical processing of theoperation data and the maintenance data from numerous hydraulicexcavators. The data indicating the maintenance timing for each machinenumber and model type calculated at the maintenance timing calculationunit 152 are transmitted to the hydraulic excavator classified under thecorresponding machine number and model type through a communicationtransmission unit 153 and then via the electric communication circuitexplained earlier.

[0090] Next, details of the data transmission/reception processingachieved through the bidirectional communication between the maintenancemonitor device 141 provided at the individual hydraulic excavators111A˜111C and the management server 112 are explained. FIG. 12 presentsa flowchart of the bidirectional data exchange between the maintenancemonitor device of a hydraulic excavator and the management server. Theprograms for executing the processing are stored in advance at storagedevices (not shown) within the maintenance monitor device 141 and themanagement server 112.

[0091] At each hydraulic excavator, its maintenance monitor device 141stores with a predetermined timing the operation data indicating theoperating state of the mechanical parts engaged in operation on a dailybasis (step S111). In the operation data recording processing, the CPU143 takes in operation signals via the various operation sensors 148mentioned earlier and stores them as operation data into the storageunit 144. Information indicating the model type and machine number isappended to the operation data stored in the storage unit 144. As theoperation data are accumulated over a specific length of time at thestorage unit 144, the CPU 143 executes processing for transmitting theoperation data stored in the storage unit 144 to the management server112 on a regular basis (e.g., every 100 engine operating hours) (stepS112). The operation data are transmitted in response to the processingexecuted by the CPU 143 via the communication interface 147, thecommunication device 150 and the electrical communication lineconstituted of the communication satellite 118 and the like (through atransmission procedure P111). The operation data being transmitted areappended with the data indicating the model type and machine number ofthe corresponding hydraulic excavator.

[0092] Upon receiving the operation data transmitted from themaintenance monitor device 141 of the hydraulic excavator (through thetransmission procedure P111) at the communication reception unit 151,the management server 112 stores the received operation data incorrespondence to the model type and machine number into the operationdatabase 116 (step S121). Next, the maintenance timing calculation unit152 calculates the maintenance timing for the individualmaintenance-requiring parts by using a formula conforming to thepredetermined criteria (step S122). During the maintenance timingcalculation processing, the processing details recorded in themaintenance database 117 are referenced for the calculation. Each set ofmaintenance timing data is calculated in correspondence to a givenmaintenance requiring part. The maintenance timing data obtained throughthe maintenance timing calculation processing (step S122) aretransmitted as maintenance information to the maintenance monitor device141 of the corresponding hydraulic excavator (step S123) via thecommunication transmission unit 153 together with a correspondingcommand (message). The maintenance information is transmitted from themanagement server 112 to the maintenance monitor device 141 through theelectrical communication line mentioned earlier (through a transmissionprocedure P112).

[0093] At the maintenance monitor device 141, the maintenanceinformation transmitted from the management server 112 is taken into theCPU 143 via the communication device 150 and the communication interface147, and the CPU 143 displays the maintenance information at the displaydevice 149 via the display interface 146 (step S113). An example of adisplay mode that may be assumed at the display device 149 is shown atthe on-vehicle display device 126 of the hydraulic excavator 111B inFIG. 9.

[0094] Subsequently, a service engineer performs maintenance work on thehydraulic excavator in conformance to the maintenance informationprovided by the management server 112. Under normal circumstances, theoperator of the hydraulic excavator checks the contents of the displaybrought up at the display device 149, verifies the items to be servicedand the timing of the maintenance and places a request to the serviceengineer (or a maintenance technician) for maintenance service. Theservice engineer performs the maintenance work as indicated at thedisplay device 149 and once the maintenance work is completed (stepS114), the service engineer turns on the maintenance complete switch 127to signal work completion. In response to the ON operation of themaintenance complete switch 127, an ON signal is input to the CPU 143and thus, the CPU 143 executes work complete switch detection processing(step S115). Following the work complete switch detection processing,the CPU 143 executes processing for transmitting the maintenance data tothe management server 112 (step S116). During the maintenance datatransmission processing, the data including the model type and machinenumber, the maintenance item and the length of operating time are readfrom the storage unit 144 and the data thus read out are transmitted tothe management server 112 via the communication interface 147, thecommunication device 150 and the electrical communication line (throughtransmission procedure P113). At the management server 112, themaintenance data that have been received are recorded into themaintenance database 117. The recorded maintenance data are incorporatedwith the basic data for the next maintenance timing calculationprocessing (step S122) to be used for the next maintenance forecastcalculation.

[0095] In the structure described above, a plurality of sets ofmaintenance information may be brought up on display at the displaydevice 149 of the maintenance monitor device 141. In this case,maintenance work is performed in correspondence to each of the pluralityof sets of maintenance information on display. An ON operation of themaintenance complete switch 127 to signal a work completion may beperformed upon completion of each maintenance work operation or it maybe performed upon completion of the entire series of maintenance work.

[0096] Failure repair work may be executed during the maintenance workthe completion of which is signaled through the maintenance completeswitch 127 in the structure described above, and accordingly, themaintenance data may contain failure location data indicating thelocation of a failure in the hydraulic excavator. When a failure occursat the hydraulic excavator, requiring repair work other than themaintenance work which is executed as directed by the management server112, information related to the failure repair can be transmitted to themanagement server 112 by using the maintenance complete switch 127 andthe failure repair information can be recorded into the maintenancedatabase.

[0097] The data exchange achieved through the bidirectionalcommunication between the maintenance monitor device 141 and themanagement server 112 is performed individually between the each of thehydraulic excavators 111A˜111C and the management server 112.

[0098] By adopting the third embodiment explained above, in whichbidirectional communication is achieved between the center server andeach of a plurality of working machines through the electricalcommunication line constituted of a communication satellite, theInternet and the like, a maintenance monitor device that collectsmaintenance data necessary for the maintenance management and stores themaintenance data in a storage unit is provided in each working machineand the maintenance data are automatically transmitted to the centerserver as an operating means for signaling a work completion is operatedupon the completion of the maintenance work, the manual input operationnormally performed by the service engineer or the like in the relatedart is eliminated and a higher degree of reliability is achieved throughthe automatic transmission of the maintenance data.

[0099] In addition, the center server, which prepares maintenanceinformation indicating a specific maintenance-requiring part andmaintenance timing for each working machine based upon the operationdata and the maintenance data stored in the database and transmits themaintenance information thus prepared to the corresponding workingmachine to be referenced by the operator, is enabled to execute themaintenance work with reliability.

[0100] While an explanation is given above in reference to theembodiments on an example in which the present invention is adopted inconjunction with hydraulic excavators, the present invention is notlimited to this example. The present invention may instead be adopted inconjunction with cranes or other types of construction working machines(construction machinery). In addition, the present invention may beadopted in conjunction with working machines other than constructionworking machines, as long the working machines are engaged in operationat work sites and a management center can be connected with the workingmachines through a communication line which enables bidirectionalcommunication.

[0101] While an explanation is given above in reference to theembodiments on an example in which transmission/reception is achievedthrough a communication satellite, the application of the presentinvention is not restricted by these particulars. For instance, datatransmission/reception may be achieved by using a mobile communicationsystem such as a mobile telephone (a cellular phone) or a PHS telephone,or it may be achieved by using another wireless system as well.

[0102] While an explanation is given above in reference to theembodiments on an example in which the programs executed by the workingmachines and the management server at the center are stored in advancein the internal storage devices, the present invention is not limited tothis example. For instance, the programs may be provided in recordingmedia such as CD-ROMs 21 and 35 in FIG. 1. Alternatively, the programsmay be provided by a program server connected via the Internet.Furthermore, the working machine program may be provided by themanagement server in FIG. 1 or FIG. 6. When the programs are providedvia the Internet and a communication satellite, they should be embodiedas data signals on carrier waves which are transmitted via acommunication line. In short, the programs can be distributed as acomputer readable computer program product assuming any of various modesincluding a recording medium and a carrier wave.

[0103] The structural features, the shapes, the dimensions and thepositional relationships explained in reference to the embodiments aboverepresent an approximate example provided to facilitate understandingand implementation of the present invention and the numerical valuesreferred to above also represent examples. Accordingly, the presentinvention is not limited to the embodiments explained above and variousmodifications may be realized without departing from the scope of thetechnical concept of the present invention.

1. A working machine failure diagnosis method for performing a failurediagnosis by transmitting and receiving signals through communicationdevices provided at a working machine and at an information managementcenter comprising: a first step in which a first signal related to afailure of the working machine is generated at the working machine andthe first signal is transmitted to the information management centerfrom the working machine via the communication devices; a second step inwhich, after the first signal is transmitted, the information managementcenter generates a second signal for identifying a location of thefailure based upon the first signal and the second signal is thentransmitted from the information management center to the workingmachine via the communication devices; and a third step in which failureinformation corresponding to the first signal and the second signal isprovided to an operator.
 2. A working machine failure diagnosis methodaccording to claim 1, wherein: the first step starts upon a detection ofan abnormal state at the working machine.
 3. A working machine failurediagnosis method according to claim 1, wherein: the first step starts asan abnormality occurrence signal is input at the working machine when anabnormality has occurred at the working machine.
 4. A working machinefailure diagnosis method according to claim 1, further comprising: afourth step in which a signal related to a service request for theidentified failure location is transmitted from the working machine tothe information management center; and a fifth step in which a servicingcost and a length of servicing time are calculated at the informationmanagement center based upon the signal related to the service requestand information indicating the cost and the length of time istransmitted to the working machine.
 5. A working machine failurediagnosis method according to claim 1, further comprising: a fourth stepin which a signal related to a service request for the identifiedfailure location is transmitted from the working machine to theinformation management center; and a fifth step in which a time point atwhich a service person is expected to arrive at a site is calculated atthe information management center based upon the signal related to theservice request and information indicating the time point is transmittedto the working machine.
 6. A working machine failure diagnosis systemcomprising: a first signal generating device that generates at a workingmachine a first signal related to a failure of the working machine; afirst transmission device that transmits the first signal from theworking machine to an information management center; a second signalgenerating device that generates at the information management center asecond signal for identifying a location of the failure based upon thefirst signal after the first signal is transmitted thereto; a secondtransmission device that transmits the second signal from theinformation management center to the working machine; and an informingdevice that provides an operator with failure information correspondingto the first signal and the second signal.
 7. A working machine failurediagnosis system according to claim 6, wherein: the working machineincludes a detection device that detects an abnormal state therein; andwhen an abnormal state is detected by the detection device, the firstsignal generating device generates the first signal based upon detectionresults.
 8. A working machine failure diagnosis system according toclaim 6, wherein: the working machine includes an operating unit that isoperated when an abnormality occurs therein; and when an abnormalityoccurrence signal is input through the operating unit, the first signalgenerating device generates the first signal based upon the abnormalityconcurrence signal.
 9. A working machine failure diagnosis systemaccording to claim 6, wherein: the second signal contains informationfor identifying the failure location; and the informing device informsthe operator of the identified failure location.
 10. A working machinefailure diagnosis system according to claim 9, wherein: the informationmanagement center includes a service management device that calculates aservicing cost and a length of servicing time after a signal related toa service request is transmitted from the working machine followingidentification of the failure location; and the second signal generatingdevice generates the second signal that contains information indicatingthe servicing cost and length of servicing time.
 11. A working machinefailure diagnosis system according to claim 9, wherein: the informationmanagement center includes a schedule management device that calculatesa time point at which a service person is expected to arrive at a siteafter a signal related to a service request is transmitted from theworking machine following identification of the failure location; andthe second signal generating device generates the second signal thatcontains information indicating the arrival time point.
 12. A workingmachine comprising: a signal generating device that generates a signalrelated to failure information; a transmission device that transmits thesignal which has been generated to an information management center; areception device that receives a signal related to a failure diagnosisreturned from the information management center in response to thesignal transmitted via the transmission device; and an informing devicethat provides failure information based upon the signal that has beenreceived.
 13. A working machine according to claim 12, furthercomprising: an automatic abnormality detection device that automaticallydetects an abnormal state in the working machine; and the signalgenerating process generates the signal related to the failureinformation when the abnormal state is detected by the automaticabnormality detection device.
 14. A working machine according to claim12, further comprising: an input device through which a failurediagnosis instruction is received from an operator; and an abnormalitydetection device that detects whether or not an abnormal state ispresent in the working machine when the failure diagnosis instruction isreceived through the input device, wherein: the signal generatingprocess generates the signal related to the failure information when theabnormal state is detected by the abnormality detection device.
 15. Aworking machine according to claim 12, wherein: the signal generatingdevice also generates a signal related to a service request for anidentified failure location; the transmission device transmits thesignal related to the service request to the information managementcenter; the reception device receives a signal related to a servicingcost and a length of servicing time generated at the informationmanagement center based upon the signal related to the service request;and the informing device provides information related to the servicingcost and the length of servicing time based upon the signal related tothe cost and the length of time which has been received.
 16. A workingmachine according to claim 12, wherein: the signal generating devicefurther generates a signal related to a service request for anidentified failure location; the transmission device transmits thesignal related to the service request to the information managementcenter; the reception device receives a signal related to a time pointat which a service person is expected to arrive at a site generated atthe information management center based upon the signal related to theservice request; and the informing device provides information relatedto the time point at which the service person is expected to arrive atthe site based upon the signal related to the arrival time point whichhas been received.
 17. A computer program product that can be read by acomputer installed in a working machine, containing a working machinefailure diagnosis program, the working machine failure diagnosis programcomprising: a signal generation instruction code for generating a signalrelated to failure information; a transmission instruction code fortransmitting the generated signal to an information management center; areception instruction code for receiving a signal related to a failurediagnosis returned from the information management center in response tothe signal transmitted in conformance to the transmission instructioncode; and an informing instruction code for providing failureinformation based upon the received signal.
 18. A computer programproduct according to claim 17, wherein the computer program product is arecording medium having the working machine failure diagnosis programrecorded therein.
 19. A computer program product according to claim 17,wherein the computer program product is a carrier wave on which theworking machine failure diagnosis program is embodied as a data signal.20. An information management center that exchanges signals with aworking machine comprising: a reception device that receives a signalrelated to failure information transmitted from the working machine; asignal generating device that generates a response signal related to afailure diagnosis in response to the signal; and a transmission devicethat transmits the response signal to the working machine.
 21. Acomputer program product that can be read by a computer installed at aninformation management center engaged in signal exchange with a workingmachine, containing a working machine failure diagnosis program, theworking machine failure diagnosis program comprising: a receptioninstruction code for receiving a signal related to failure informationtransmitted from the working machine; a signal generating instructioncode for generating a response signal related to a failure diagnosis inresponse to the signal; and a transmission instruction code fortransmitting the response signal to the working machine.
 22. A computerprogram product according to claim 21, wherein the computer programproduct is a recording medium having the working machine failurediagnosis program recorded therein.
 23. A computer program productaccording to claim 21, wherein the computer program product is a carrierwave on which the working machine failure diagnosis program is embodiedas a data signal.
 24. A working machine maintenance system comprising: aplurality of working machines; and a center server that managesmaintenance on the plurality of working machines by engaging in dataexchange through bidirectional communication with each of the pluralityof working machines via a communication line, wherein: the workingmachines each include an operation data storage device that storesoperation data and maintenance data, an operation device operated toenter a maintenance work completion, a data transmission device thattransmits the operation data, maintenance work completion data providedthrough the operation device and the maintenance data to the centerserver, a data reception device that receives data related tomaintenance information transmitted from the center server and a displaydevice at which the maintenance information is displayed; and the centerserver includes a data reception device that receives the operationdata, the maintenance work completion data and the maintenance data thathave been transmitted, an operation database in which the operation dataare stored, a maintenance database in which the maintenance data arestored, a calculation device that calculates maintenance timing basedupon the operation data stored in the operation database and themaintenance data stored in the maintenance database and a datatransmission device that transmits data related to the maintenanceinformation including the maintenance timing to a working machine.
 25. Aworking machine maintenance system according to claim 24, wherein:maintenance work, a completion of which is signaled through an inputoperation at the operation device, includes failure repair work; and themaintenance data include failure location data indicating a failurelocation at the working machine.
 26. A working machine comprising: acommunication device that exchanges information via a communication linethrough bidirectional communication with a center server managingmaintenance on a plurality of working machines; an operation device atwhich an input operation signaling a maintenance work completion isreceived; a storage device in which maintenance completion informationrelated to the maintenance work completion is stored; and a controldevice that transmits the maintenance completion information stored inthe storage device to the center server via the communication devicewhen the input operation signaling the maintenance work completion isreceived at the operation device.
 27. A working machine according toclaim 26, further comprising: a display device, wherein: the controldevice receives maintenance instruction information related to amaintenance instruction transmitted from the center server via thecommunication line and displays the maintenance instruction informationthat has been received at the display device.
 28. A working machineaccording to claim 27, wherein: operation information related to anoperation of the working machine is stored in the storage device; andthe control device transmits the operation information stored in thestorage device to the center server via the communication device withpredetermined timing.
 29. A computer program product that can be read bya computer installed at a working machine, containing a working machinemaintenance program, the working machine maintenance program comprising;an operation instruction code for receiving an input operation signalinga maintenance work completion at the working machine via an inputdevice; a storage instruction code for storing maintenance completioninformation related to the maintenance work completion at the workingmachine into a storage device; and a transmission instruction code fortransmitting the maintenance completion information stored in thestorage device via a communication device to a center server managingmaintenance on a plurality of working machines upon receiving the inputoperation signaling the maintenance work completion.
 30. A computerprogram product according to claim 29, wherein the computer programproduct is a recording medium having the working machine maintenanceprogram recorded therein.
 31. A computer program product according toclaim 29, wherein the computer program product is a carrier wave onwhich the working machine maintenance program is embodied as a datasignal.
 32. A center server that manages maintenance on a workingmachine, comprising: a communication device that exchanges informationwith a working machine via a communication line through bidirectionalcommunication; a maintenance database in which information related tothe maintenance on the working machine is stored; and a control devicethat receives maintenance completion information related to amaintenance work completion at the working machine transmitted from theworking machine via the communication device and stores the receivedmaintenance completion information into the maintenance database.
 33. Acenter server according to claim 32, further comprising: an operationdatabase in which operation information related to an operation of theworking machine is stored, wherein: the control device receives theoperation information transmitted from the working machine via thecommunication line and stores the received operation information intothe operation database.
 34. A center server according to claim 33,wherein: the control device generates maintenance instructioninformation related to a maintenance instruction for the working machinebased upon the information related to the maintenance on the workingmachine stored in the maintenance database and the operation informationrelated to the operation of the working machine stored in the operationdatabase and transmits the maintenance instruction information that hasbeen generated to the working machine via the communication device. 35.A computer program product that can be read by a center server managingmaintenance on a working machine, containing a working machinemaintenance management program, the working machine maintenancemanagement program comprising: a reception instruction code forreceiving maintenance completion information related to a maintenancework completion at the working machine transmitted from the workingmachine via a communication device; and a storage instruction code forstoring the maintenance completion information that has been receivedinto a maintenance database.
 36. A computer program product according toclaim 35, wherein the computer program product is a recording mediumhaving the working machine maintenance program recorded therein.
 37. Acomputer program product according to claim 35, wherein the computerprogram product is a carrier wave on which the working machinemaintenance program is embodied as a data signal.